tools: add zmqsend tool, useful to test the zmq filters

1 files changed, 26 insertions, 0 deletions

diff --git a/doc/filters.texi b/doc/filters.texi
index f14cf6b557..def2751ba7 100644
--- a/doc/filters.texi
+++ b/doc/filters.texi
@@ -8413,6 +8413,32 @@ will send a reply to the client, adopting the format:
 
 @var{MESSAGE} is optional.
 
+@subsection Examples
+
+Look at @file{tools/zmqsend} for an example of a zmq client which can
+be used to send commands processed by these filters.
+
+Consider the following filtergraph generated by @command{ffplay}
+@example
+ffplay -dumpgraph 1 -f lavfi "
+color=s=100x100:c=red  [l];
+color=s=100x100:c=blue [r];
+nullsrc=s=200x100, zmq [bg];
+[bg][l]   overlay      [bg+l];
+[bg+l][r] overlay=x=100 "
+@end example
+
+To change the color of the left side of the video, the following
+command can be used:
+@example
+echo Parsed_color_0 c yellow | tools/zmqsend
+@end example
+
+To change the right side:
+@example
+echo Parsed_color_1 c pink | tools/zmqsend
+@end example
+
 @c man end MULTIMEDIA FILTERS
 
 @chapter Multimedia Sources